PostgreSQL change data capture and delivery to Yandex Data Streams
You can track data changes in a Managed Service for PostgreSQL source cluster and send them to a Data Streams target cluster using Change Data Capture (CDC).
To set up CDC using Data Transfer:
If you no longer need the resources you created, delete them.
Getting started
Prepare the infrastructure:
-
Create a Managed Service for PostgreSQL source cluster in any suitable configuration with publicly available hosts and the following settings:
- DB name:
db1
- Username:
pg-user
- DB name:
-
Set up security groups and make sure they allow cluster connections.
-
Grant the
mdb_replication
role to thepg-user
. -
Create a Managed Service for YDB database named
ydb-example
in any suitable configuration. -
Create a service account named
yds-sa
with theyds.editor
role. The transfer will use it to access Data Streams.
-
If you do not have Terraform yet, install it.
-
Get the authentication credentials. You can add them to environment variables or specify them later in the provider configuration file.
-
Configure and initialize a provider. There is no need to create a provider configuration file manually, you can download it
. -
Place the configuration file in a separate working directory and specify the parameter values. If you did not add the authentication credentials to environment variables, specify them in the configuration file.
-
Download the postgresql-yds.tf
configuration file to the same working directory.This file describes:
- Network.
- Subnet.
- Security group required to connect to a cluster.
- Managed Service for PostgreSQL source cluster.
- Managed Service for YDB database.
- Service account to use to access Data Streams.
- Source endpoint.
- Transfer.
-
In the
postgresql-yds.tf
file, specify the PostgreSQL user password. -
Make sure the Terraform configuration files are correct using this command:
terraform validate
If there are any errors in the configuration files, Terraform will point them out.
-
Create the required infrastructure:
-
Run the command to view planned changes:
terraform plan
If the resource configuration descriptions are correct, the terminal will display a list of the resources to modify and their parameters. This is a test step. No resources are updated.
-
If you are happy with the planned changes, apply them:
-
Run the command:
terraform apply
-
Confirm the update of resources.
-
Wait for the operation to complete.
-
All the required resources will be created in the specified folder. You can check resource availability and their settings in the management console
. -
Set up the transfer
-
Create a Data Streams data stream named
mpg-stream
. -
Connect to the Managed Service for PostgreSQL cluster, create a table named
measurements
in thedb1
database, and populate it with data:CREATE TABLE measurements ( device_id varchar(200) NOT NULL, datetime timestamp NOT NULL, latitude real NOT NULL, longitude real NOT NULL, altitude real NOT NULL, speed real NOT NULL, battery_voltage real, cabin_temperature real NOT NULL, fuel_level real, PRIMARY KEY (device_id) ); INSERT INTO measurements VALUES ('iv9a94th6rzt********', '2022-06-05 17:27:00', 55.70329032, 37.65472196, 427.5, 0, 23.5, 17, NULL), ('rhibbh3y08qm********', '2022-06-06 09:49:54', 55.71294467, 37.66542005, 429.13, 55.5, NULL, 18, 32);
-
Create a target endpoint of the
Data Streams
type with the following settings:- Database:
ydb-example
- Stream:
mpg-stream
- Service account:
yds-sa
- Database:
-
Create a source endpoint and a transfer.
ManuallyTerraform-
Create a source endpoint of the
PostgreSQL
type and specify the cluster connection parameters in it:- Installation type:
Managed Service for PostgreSQL cluster
- Managed Service for PostgreSQL cluster:
<name_of_PostgreSQL_source_cluster>
from the drop-down list - Database:
db1
- User:
pg-user
- Password:
pg-user
password
- Installation type:
-
Create a transfer of the Replication type that will use the created endpoints.
-
In the
postgresql-yds.tf
file, specify the following variables:yds_endpoint_id
: ID of the target endpoint.transfer_enabled
: Set to1
to enable transfer creation.
-
Make sure the Terraform configuration files are correct using this command:
terraform validate
If there are any errors in the configuration files, Terraform will point them out.
-
Create the required infrastructure:
-
Run the command to view planned changes:
terraform plan
If the resource configuration descriptions are correct, the terminal will display a list of the resources to modify and their parameters. This is a test step. No resources are updated.
-
If you are happy with the planned changes, apply them:
-
Run the command:
terraform apply
-
Confirm the update of resources.
-
Wait for the operation to complete.
-
-
-
Activate the transfer
-
Activate the transfer and wait for its status to change to Replicating.
-
Make sure the data from the source has been moved to the Data Streams stream:
Management consoleAWS CLI- In the management console
, select Data Streams. - Select the target stream from the list and go to
Data viewer. - Make sure
shard-000000
contains messages with the source table rows. To view message details, click .
-
Configure the environment for Data Streams.
-
Read the stream data using:
- In the management console
Test the replication process
-
Connect to the source cluster.
-
Add a new row to the
measurements
table:INSERT INTO measurements VALUES ('ad02l5ck6sdt********', '2022-06-05 17:27:00', 55.70329032, 37.65472196, 427.5, 0, 23.5, 19, 45);
-
Make sure the new row is shown in the Data Streams stream.
Delete the resources you created
Note
Before deleting the created resources, deactivate the transfer.
Some resources are not free of charge. To avoid paying for them, delete the resources you no longer need:
Delete the other resources depending on how they were created:
-
In the terminal window, go to the directory containing the infrastructure plan.
-
Delete the
postgresql-yds.tf
configuration file. -
Make sure the Terraform configuration files are correct using this command:
terraform validate
If there are any errors in the configuration files, Terraform will point them out.
-
Confirm updating the resources.
-
Run the command to view planned changes:
terraform plan
If the resource configuration descriptions are correct, the terminal will display a list of the resources to modify and their parameters. This is a test step. No resources are updated.
-
If you are happy with the planned changes, apply them:
-
Run the command:
terraform apply
-
Confirm the update of resources.
-
Wait for the operation to complete.
-
All the resources described in the
postgresql-yds.tf
configuration file will be deleted. -